This PDF file contains the front matter associated with SPIE Proceedings volume 7425, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Optical systems are designed for a great variety of purposes and are influenced by significantly differing requirements.
Due to these differences, material trade studies are part of almost all optical system designs. These trade studies must use
objective comparative parameters in order to choose the best optical and structural materials for the optical system.
Material figures of merit such as specific stiffness and thermal stability are traditional figures of merit used in materials
trade studies. In this paper, we explore additional material figures of merit arising from both technical and programmatic
concerns. We show how to use all of these figures of merit simultaneously in a systematic approach to optimum
materials selection.

During the past several years, ECM carried out a large trade-off project with the objective of comparing CTEmeasurements
of samples of our Cesic® MF ceramic material performed by laboratories in Europe, USA, and Japan.
Our focus was on CTE measurements in the cryo-environment down to less than 20 K.
From past experience, we realized that we needed to pay particular attention to making the samples sufficiently large to
obtain realistic measurement results that relate to actual applications, especially for temperatures below that of LN2.
Thus, we made the samples as large as allowed by the size limitations of the test equipment at the different laboratories,
namely, from 15 mm to 250 mm in length.
The scatter in the test data obtained by the different laboratories was so large that the results were unreliable and not very
useful, which we interpreted to be principally due to the large length range of the samples.
Based on these results, we selected Mitsubishi Electric Corporation (MELCO), Japan, for follow-up cryo-measurements
because they were able to test 250-mm long samples down to < 10 K. More recently MELCO enlarged their cryo-test
equipment to sample sizes as large as 500 mm and with the rather high measurement accuracy of 0.1 ppm/K.
In this paper we present the CTE measurement data obtained by the different laboratories and describe the new cryo-test
facility at MELCO.

This review paper summarizes the extensive investigations that have been performed at SCHOTT to achieve a deeper
understanding of the CTE homogeneity of ZERODUR® within single blanks and the casted formats (boules). Especially
for the upcoming Extremely Large Telescope (ELT) projects like E-ELT or TMT with at least several hundreds of
mirror segments the reproducibility of the mean CTE, CTE homogeneity and axial gradient is very important while
keeping the CTE quality assurance process economic at the same time. Statistics of CTE homogeneity measurements on
a ZERODUR® boule suitable for an economical production of ELT mirror substrates using the improved dilatometer
will be presented. It will be shown, that it is possible to achieve tight CTE specifications by utilisation of processes
existing at SCHOTT, while at the same time guaranteeing a long term reproducibility. The CTE measurement is
optimized for a temperature interval from 0°C to 50°C. We developed a model to extrapolate the CTE behaviour to
specific temperature conditions at the telescope site.

A prototype for a compact and relatively simple system capable to measure the refraction index of glasses, between 0.4
to 1.7 micron, at room and cryogenic temperatures (T=100-300 K), with an absolute precision of few parts of 100'000
has been developed at INAF facilities in Merate. It is based onto the measurement of the deviation angle of
monochromatic light passing through a prism sample placed in the cryogenic chamber. The precision of the
measurements depends on many factors, in particular the angle measurement and the thermal stability. Different
subsystems have been studied to keep all these parameters under accurate control. One of the main issues has been the
trade-off between the simplicity of the set-up and the precision of the refractive index measurement.

A brief overview is provided on three common methods of nondestructive evaluation (NDE), Ultrasonic Testing (UT),
Radiographic Testing (RT) and Eddy Current (EC). These methods vary in the physics applied to the testing or
evaluation process while specific techniques vary in the way each method may be applied. Understanding the physics
behind each method and constraints of each technique helps us understand the capabilities and limitations of the
inspection. Recognizing the capabilities and limitation of these NDE Techniques helps us properly design the inspection,
collect and process data and draw appropriate conclusions.

Two types of SiC plates, differing in their manufacturing processes, were interrogated using a variety of NDE
techniques. The task of evaluating the materials properties of these plates was a challenge due to their non-uniform
thickness. Ultrasound was used to estimate the Young's Modulus and calculate the thickness profile and Poisson's
Ratio of the plates. The Young's Modulus profile plots were consistent with the thickness profile plots, indicating
that the technique was highly influenced by the non-uniform thickness of the plates. The Poisson's Ratio is
calculated from the longitudinal and shear wave velocities. Because the thickness is cancelled out, the result is
dependent only on the time of flight of the two wave modes, which can be measured accurately. X-Ray was used to
determine if any density variations were present in the plates. None were detected suggesting that the varying time of
flight of the acoustic wave is attributed only to variations in the elastic constants and thickness profiles of the plates.
Eddy Current was used to plot the conductivity profile. Surprisingly, the conductivity profile of one type of plates
varied over a wide range rarely seen in other materials. The other type revealed a uniform conductivity profile.

Silicon carbide mirror blank materials were characterized using ultrasound phased array technology to
determine the feasibility of using this method for rapidly characterizing material homogeneity and locate anomalous
flaws. A 10MHz 64 element linear probe was used to measure and image the top and bottom surface reflected signal
peak amplitudes. C-scan images located the presence of possible sub-surface heterogeneities as well as surface scratches
invisible to the eye. Bottom surface scans located variations in homogeneity within the sample bulk. High frequency
ultrasound phased array was found to be well suited for detailed characterization of SiC mirror blanks.

The Aerospace Corporation is developing a space qualification method for silicon carbide optical systems that covers
material verification through system development. One of the initial efforts has been to establish testing protocols for
material properties. Three different tests have been performed to determine mechanical properties of SiC: modulus of
rupture, equibiaxial flexural strength and fracture toughness. Testing materials and methods have been in accordance
with the respective ASTM standards. Material from four vendors has been tested to date, as part of the MISSE flight
program and other programs. Data analysis has focused on the types of issues that are important when building actual
components- statistical modeling of test results, understanding batch-to-batch or other source material variations, and
relating mechanical properties to microstructures. Mechanical properties are needed as inputs to design trade studies and
development and analysis of proof tests, and to confirm or understand the results of non-destructive evaluations of the
source materials. Measuring these properties using standardized tests on a statistically valid number of samples is
intended to increase confidence for purchasers of SiC spacecraft components that materials and structures will perform
as intended at the highest level of reliability.

An important space application for structural ceramics is the large (~1m diameter) silicon carbide mirrors used in
telescopes. However, all ceramics have two drawbacks. First, ceramics are brittle and have a low resistance to
catastrophic flaw propagation during service. Second, ceramics have a population of preexisting flaws produced during
manufacturing.
The most modern and successful theory of fracture control is "defect tolerant design", which recognizes that engineering
structures are inherently flawed and which is used to predict the structure's service life. As part of defect tolerant design,
the size of the inherent flaws is controlled by combining nondestructive evaluation (which has a threshold for the
smallest flaw that can be reliably identified) and proof testing (which provides an independent measurement of the
largest preexisting flaw).
We are developing a novel proof test that is specialized for a lightweighted ceramic mirror. The most promising loading
method is identified and an experimental implementation has been proposed and designed for future development.

This annual review documents our progress towards inexpensive mass production of silicon carbide mirrors and optical
structures. Results are provided for a NASA Small Business Technology Transfer (STTR) X-Ray Mirror project. Trex
partnered with the University of Alabama-Huntsville Center for Advanced Optics (UAH-CAO) to develop fabrication
methods for polished cylindrical and conical chemical vapor composite (CVCTM) SiC mandrels. These mandrels are
envisioned as pre-forms for the replication of fused silica x-ray optics to be eventually used in the International X-Ray
Observatory (IXO). CVC SiCTM offers superior high temperature stability, thermal and mechanical performance and
polishability required for this precision replication process. In this program, Trex fabricated prototype mandrels with
design diameters of 10.5cm, 20cm and 45cm.
UAH-CAO was Trex's university partner in this effort and worked on polishing and metrology of the unusual x-ray
mandrel geometries. UAH-CAO successfully developed an innovative interferometric method for measuring the CVC
SiCTM x-ray mandrels based on a precision cylindrical lens system. UAH-CAO also developed finishing and polishing
methods for CVC SiCTM that utilized a Zeeko IRP200 computer controlled polishing tool. The three technologies key
technologies demonstrated in this program (near net shape forming of CVC SiCTM mandrels, the x-ray mandrel
metrology and free-form polishing capability on CVC SiCTM) could enable cost-effective manufacture of the x-ray
mandrels required for the International X-Ray Observatory (IXO).

To reduce the finishing costs of silicon carbide mirror substrates, silicon claddings are applied allowing the surfaces to
be more easily diamond turned and polished than the bare chemical vapor deposited (CVD) silicon carbide or bimodal
reaction bonded SiC (RB-SiC). The benefits of using silicon as the optical face will be reviewed as will the process for
applying plasma enhanced chemical vapor (PE-CVD) deposited amorphous silicon cladding on substrates. Using one
mirror as an example, the successful finishing results will be shared.

In support of a new airborne telescope system the Multi-Spectral Telescope for a new Reconnaissance Program ECM
was contracted by Carl Zeiss Optronics to produce 20 mirrors made of HB-Cesic®, each mirror with a diameter of 315
mm. The contract requirements were that the mirrors remain stable under extreme mechanical and thermal loads and that
the production schedule is 12 months.
The main challenges of the project were achieving consistent optical performance of the mirrors and meeting the tight
schedule of delivering the mirrors, in lots of four, every two months for a total delivery time of twelve months.
In this paper we present the lessons learned in producing the HB-Cesic® mirrors, including all the steps up to the final
integration of the mirrors into the telescope system and establishing reliable repeatability of the production cycles.

Single crystal silicon (SCSi) is light, strong, has excellent thermal properties, is readily available and cost and delivery
are competitive with, and probably better than, either beryllium or silicon carbide. In addition, SCSi's zero-defect crystal
structure enables polishing to near-perfect surfaces.
Recent developments in direct bonding have led to simple methods of attaching SCSi, a brittle material, to enhance its
high compressive strength and avoid tensile/brittle failures. Dynamic testing of a bonded assembly has demonstrated
high resonant frequencies and damping capacity. Other recent test results have shown the excellent temporal and thermal
stability of both monolithic and bonded mirror specimens.
So why not choose silicon?

SPIRALE is a French Earth observation demonstration project consisting of two satellites. In support of the project and
under contract with Thales Alenia Space, ECM manufactured two fully integrated all-Cesic® telescopes, composed of
super-light-weighted complex monolithic structures, including two off-axis aspheric mirrors per telescope with
integrated interfaces for mounting.
The all-Cesic telescope assembly was tested under shock and vibration loads, and by exposure to realistic in-flight
thermal environments.
In this paper we describe the space-qualified process of manufacturing such high-precision space telescopes based on our
Cesic® technology; the advantages of our Cesic® technology compared to traditional materials, such as metals or glass
ceramics; and some of the test results.
This project demonstrates that all-Cesic® telescopes have great potential for future space applications, especially under
cryogenic conditions, due to their athermal characteristics and the great versatility of the Cesic® manufacturing process.

BAE Systems has developed an all-beryllium-aluminum version of the F-9120; a compact, lightweight, dual-band
Electro-Optical/Infrared (EO/IR) long range sensor for high altitude tactical reconnaissance applications. The use of
beryllium-aluminum as a common mirror and structure material provides a novel sensor solution that satisfies the
military's need to gather high quality, long range, simultaneous, visible and infrared imagery at a lower cost. This paper
will discuss the formulation and implementation of BAE Systems innovative material approach as well as its
manufacturing and performance advantages.

The Near Infrared Camera (NIRCam) Optical Bench Assembly (OBA) is a I-220H beryllium adhesively-bonded
structure designed to operate at 35K. To support design activities, an adhesive testing program was performed, with
particular emphasis on adhesive allowables at 35K. The geometries of the samples were designed to emulate the
structural features of the OBA. The testing program is described, test data presented, and the results applied to the NIRCam OBA.

The Near Infrared Camera (NIRCam) is the primary imaging instrument on the James Webb Space Telescope. The
primary structure for NIRCam is called the Optical Bench Assembly (OBA). The OBA is a bonded Beryllium structure
designed to operate at 35K. The structure has recently undergone thermal cycling to 35K followed by structural
qualification vibration testing. Analytical predictions were made of the structural performance during vibration. These
predictions closely matched the actual performance. This paper summarizes the build and assembly of the OBA, and
focuses on the qualification thermal and structural testing of the OBA. The qualification testing is described and pre-test
analysis is presented and compared with test results.

The zero-expansion glass ceramic ZERODUR® from SCHOTT is widely used for ground-based astronomical mirrors
and in industrial applications. This paper points out that it is also well suited for satellite applications, especially with
respect to the space radiation environment. Recent developments show that highly lightweighted components can be
manufactured and that such structures are strong enough to survive launch vibrations. A series of thirty reference
applications, where ZERODUR® has been or is currently used (including METEOSAT, SPOT, ROSAT, CHANDRA,
and HST), demonstrate the high and long lasting performance of ZERODUR® components in orbit. The ongoing
successful missions and upcoming new satellites continue to enlarge the space heritage of this unique material.

Recently SCHOTT has shown in a series of investigations the suitability of the zero expansion glass ceramic material
ZERODUR® for applications like mirrors and support structures of complicated design used at high mechanical loads.
Examples are vibrations during rocket launches, bonded elements to support single mirrors or mirrors of a large array, or
controlled deformations for optical image correction, i.e. adaptive mirrors.
Additional measurements have been performed on the behavior of ZERODUR® with respect to the etching process,
which is capable of increasing strength significantly. It has been determined, which minimum layer thickness has to be
removed in order to achieve the strength increase reliably.
New data for the strength of the material variant ZERODUR K20® prepared with a diamond grain tool D151 are
available and compared with the data of ZERODUR® specimens prepared in the same way. Data for the stress corrosion
coefficient n of ZERODUR® for dry and normal humid environment have been measured already in the 1980s. It has
been remeasured with the alternative double cleavage drilled compression (DCDC) method.

The pupil imaging lens (PIL) assembly is one component within the NIRCam instrument, which is the primary imaging
instrument on the James Webb Space Telescope (JWST). The main purpose of the PIL assembly is to form an image of
the eighteen primary mirror segments of the JWST onto the NIRCam focal plane arrays (FPAs). NIRCam is the only
instrument on the JWST observatory with wave front sensing (WFS) capability, and will use the PIL in conjunction with
the WFS measurements1.
The purpose of this paper is to introduce the audience to a monolithic PIL assembly created from five unique lenses
mounted to an optical baseplate. The lenses are assembled using a direct bonding method, with the aid of a diluted
potassium hydroxide solution. Described in this paper is a simple, yet precise method for aligning and assembling the
PIL optics.

A. Verneuil developed flame fusion to grow sapphire and ruby on a commercial scale around 1890. Flame fusion was
further perfected by Popov in the Soviet Union in the 1930s and by Linde Air Products Co. in the U.S. during World
War II. Union Carbide Corp., the successor to Linde, developed Czochralski crystal growth for sapphire laser materials
in the 1960s. Edge-Defined Film-Fed Growth (EFG) was invented by H. Labelle in the 1960s and the Heat Exchanger
Method (HEM) was invented by F. Schmid and D. Viechnicki in 1967. Both methods were commercialized in the
1970s. Gradient solidification was invented in Israel in the 1970s by J. Makovsky. The Horizontal Directional
Solidification Method (HDSM) was invented by Kh. S. Bagdasorov in the Soviet Union in the 1960s. Kyropoulos
growth of sapphire, known as GOI crystal growth in the Soviet Union, was developed by M. Musatov at the State
Optical Institute in St. Petersburg in the 1970s. Today, half of the world's sapphire is produced by the GOI method.

Due to their very specific set of material properties, silicon nitride and silicon carbide have gained a lot of interest in the
last 20 years. Moreover, many new approaches in technical equipment and processes were enabled with corresponding
research and production activities.
Also large efforts were made at FCT during the last years, to get able to supply even very large and complex shaped
components made of sintered silicon carbide (SSiC) and of gas pressure sintered silicon nitride (GPSN) ceramics. This
approach has opened new applications and markets for such ceramic materials. On the other side, designers and
engineers are now allowed to think much more complex in designing of ceramic components. In this paper, a new rapid
prototyping routine for very complex components as well as the corresponding materials will be presented. Components
for optical equipment in innovative avionic and space applications, and more conventional technologies are described.
Not only their unique key intrinsic properties, like high Youngs Modulus, very low CTE, very high strength and fracture
toughness for a ceramic but also newly developed and adopted shaping, sintering and machining technologies in both
green and sintered state have let to highly valued products. This enabled FCT to offer Carl Zeiss Optronics using silicon
nitride for a newly designed, very complex housing structure of an avionic pod camera. Due to a very low CTE, high
stiffness and less weight, an improved performance was reached.
Also Thales Alenia Space is engaged since some years in activities to develop and qualify Silicon nitride ceramics for
space projects. Extremely stiff, very lightweight and large truss space structures with a very low CTE, high rigidity and
no outgasing for satellites can now be realized. Deep tests sequence has been performed to qualify truss beams and end
fittings made in the same material.
Also advanced dynamic testing equipment for avionic turbine blades requires new approaches. In cooperation with
TIRA a series of shaker heads were developed which can operate at much higher frequencies and so reduce fatigue
testing time and costs. Last but not least, highly precise and thin walled disc structures with diameters up to 380 mm are
produced for wafer handling and testing equipment.

NASA's upcoming ARES V launch vehicle, with its' immense payload capacities (both volume and mass) has opened
the possibilities for a whole new paradigm of space observatories. It becomes practical to consider a monolith mirror of
sufficient size to permit significant scientific advantages, both in collection area and smoothness or figure at a reasonable
price. The technologies and engineering to manufacture and test 8 meter class monoliths is mature, with nearly a dozen
of such mirrors already in operation around the world. This paper will discuss the design requirements to adapt an 8m
meniscus mirror into a Space Telescope System, both launch and operational considerations are included. With objects
this massive and structurally sensitive, the mirror design must include all stages of the process. Based upon the
experiences of the Hubble Space Telescope, testing and verification at both component and integrated system levels are
considered vital to mission success. To this end, two different component level test methods for gravity sag (the so call
zero- gravity simulation or test mount) are proposed, with one of these methods suitable for the full up system level
testing as well.

The fabrication of lightweight mirror assemblages via a replication technique offers great potential for eliminating the
high cost and schedule associated with the grinding and polishing steps needed for conventional glass or SiC mirrors. A
replication mandrel is polished to an inverse figure shape and to the desired finish quality. It is then, coated with a
release layer, the appropriate reflective layer, and followed by a laminate for coefficient of thermal expansion (CTE)
tailorability and strength. This optical membrane is adhered to a mirror structural substrate with a low shrinkage, CTE
tailored adhesive. Afterwards, the whole assembly is separated from the mandrel. The mandrel is then cleaned and
reused for the next replication run. The ultimate goal of replication is to preserve the surface finish and figure of the
optical membrane upon its release from the mandrel. Successful replication requires a minimization of the residual
stresses within the optical coating stack, the curing stresses from the adhesive and the thermal stress resulting from CTE
mismatch between the structural substrate, the adhesive, and the optical membrane. In this paper, the results on
replicated trials using both metal/metal and ceramic/ceramic laminates adhered to light weighted structural substrates
made from syntactic foams (both inorganic and organic) will be discussed.

With the increasing complexity of optical designs flown on satellites, specialty thin film and multilayer filter coatings
are being implemented more often. Unfortunately, very little ionizing radiation testing has actually been performed on
such coatings, and certainly not completed to very high doses as might be experienced by an unshielded space optic in
orbit for many years. In this paper we present results of gamma irradiation testing on the transmission properties of
selected multilayer filters and optical coatings performed in an inert argon environment.

Cerium oxides are of interest in many applications including optical coatings, solid-state fuel cells, and catalyst supports.
Due to excellent absorption in ultraviolet (UV), these materials are also widely used as UV blocking layers in medical
glassware and aerospace windows. In this paper, we present the fabrication and characterization of cerium oxide thin
films and their potential application in UV sensing. Cerium oxides were deposited by reactive oxygen ion beam assisted
e-beam evaporation. Comparing with the films obtained without ion assistance, oxygen plasma assisted deposition
enhances refractive index from ~ 1.8 to ~ 2.2 and improves electrical resistivity from ~ 106 Ωcm to ~ 1010 Ωcm. More
importantly, the film deposited with ion assistance shows stronger blue to UV absorption observed from the
transmittance spectra, which presumably is better for UV sensing. X-ray photoelectron spectroscopy and X-ray
diffraction measurements further suggest insights in stoichiometry and crystal structures. A concept-proving photodiode
was fabricated by employing a p+-Si/CeO2/n-In2O3 heterostructure. The current-voltage characteristics exhibit obvious diode-like behavior with a current rectification ratio of ~ 105. A low leakage current in a range of 10-10 ~ 10-8 A was
achieved at reverse biases of 0 to 10 V, respectively. The diode demonstrates high photocurrent gain of ~ 100 times and
fast photoresponse under a 405 nm UV exposure.

We report on the design, application, and testing of custom protected silver and aluminum coatings for use on the Magdalena Ridge Observatory Interferometers (MROI) unit telescopes. The coatings were designed by Optical Surface Technologies (OST), and tested under normal observational conditions on Magdalena Ridge. Mirror coating samples fabricated by OST were given to MRO, and then placed in an insulated automated enclosure at the observatory site. Within the enclosure, environmental conditions such as temperature and humidity were continuously monitored. The automated enclosure was instructed to open during the night dependent upon weather conditions matching those that would occur under normal operations of the interferometer. This paper tracks the affect of the Magdalena Ridge environment on the performance of the coatings, specifically with regards to reflectivity.

The synchrotron radiation (SR) X-ray absorption fine-structure spectroscopy (XAFS) technology was employed on Si Kedge
absorption spectra for bulk 6H-SiC with different doping concentration. Their Fourier transform spectra were
analyzed, which have shown a parabolic linear distribution of bond lengths. Through combined Raman and XAFS
studies, the coincidental results could be obtained. In the Raman spectroscopy, the LO mode intensity becomes weaker
and broader as the doping concentration increases. This indicates that the crystallinity is damaged by the heavy doping
concentration. The Raman curves have been fitted by theoretical formulas and the accurate information of the intensity,
peak position, and FWHM in each TO and LO modes have been obtained. By the EXAFS and the fitting program, the
bond length of Si-C in 6H-SiC decreases as the doping concentration increases. It is believed to be caused by the
nitrogen atoms substituting for carbon atoms in the SiC lattice. But further research work is needed to identify this. The
little change in Si-Si bond length indicates the influence of doping is still under local structure, near the absorbed atoms.

This paper presents a roll-to-roll method to fabricate microlens arrays on a glass substrate by using a cost-effective
PDMS (Polydimethylsiloxane) mold. We fabricated microlens arrays mold, which was made by photoresist(AZ4620), on the silicon substrate by thermal reflow process, and transferred the pattern to PDMS film. Roll-to-roll system is a standard printing process whose roller is made of acrylic cylinder surrounded with the PDMS mold. UV resin was chosen to be the material to make microlens in rolling process with UV light curing. We investigated the quality of
microlens arrays by changing the parameters, such as embossing pressure and rolling speed, to ensure good quality of
microlens arrays.

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Journal of Applied Remote SensingJournal of Astronomical Telescopes Instruments and SystemsJournal of Biomedical OpticsJournal of Electronic ImagingJournal of Medical ImagingJournal of Micro/Nanolithography, MEMS, and MOEMSJournal of NanophotonicsJournal of Photonics for EnergyNeurophotonicsOptical EngineeringSPIE Reviews